Sweetener compositions

ABSTRACT

The invention provides a sweetener composition comprising a core nano particle in association with a sweetener carbohydrate.

The present invention relates to sweetener compositions. Moreparticularly, the present invention relates to carbohydrate sweetenercompositions having a higher sweetening power and a lower caloriccontent per weight than that of the carbohydrate component thereof, andto methods for the preparation thereof.

Sucrose, glucose, fructose and other sweet mono-saccharides anddi-saccharides are fully metabolized when consumed in food. Thus, foreach natural carbohydrate sweetener the provision of sweetnesscorrelates with the provision of calories in a rigidly fixed proportion.The present invention provides for the manipulation of this proportionso that a desired sweetness may correlate with lower calorie values.This is achieved through the presentation of the carbohydrate sweetenerin the form of a composition belonging to a class of compositionsdescribed below. Differently put, the perception of sweetness of acarbohydrate sweetener is retained while reducing the caloric valuethereof by virtue of its being provided in a composition as describedhereinafter.

More particularly, according to the present invention, there is nowprovided a sweetener composition comprising a core nano-particle incombination with a sweetener carbohydrate coating.

In preferred embodiments of the present invention, said nano-particlesare of a size of between about 3 nm and 100 nm.

In especially preferred embodiments of the present invention, saidnano-particles are of a size of between about 5 nm and 50 nm.

Preferably said nano-particles comprise exposed oxygen molecules alongthe surfaces thereof.

In especially preferred embodiment of the present invention, saidnano-particles are dispersible in water and preferably, aresubstantially water-insoluble.

Since it is intended that the sweetener compositions in at least some oftheir application be incorporated in food products, preferably saidnano-particles are food compatible.

In preferred embodiments of the present invention, said nano-particlecores are formed of inorganic nano-particles.

In especially preferred embodiment of the present invention, saidnano-particle cores are formed of nano-silicas.

In these preferred embodiments, said nano-silicas carry on their surface—OH groups and Si—O—Si chains, and the oxygen components thereof arelinked to carbohydrate groups which adhere thereto.

In other preferred embodiments of the present invention, saidnano-particle cores are formed of organic nano-particles ofpoly-carbohydrates and derivatives thereof of limited water solubility,i.e., that are substantially insoluble below 50° C.

Thus in some preferred embodiments said nano-particle cores are formedof low solubility starches.

In other preferred embodiments said nano-particle cores are formed ofnano-cellulose and nano-particles of cellulose derivatives such asethoxycellulose and cellulose acetate.

In these preferred embodiments, said nano-cellulose carries on itssurface —OH groups and C—O—C chains, and the oxygen components thereofare associated with said carbohydrate groups which adhere thereto.

As will be realized, the compositions of carbohydrates mentioned aboveconsist of discrete nano-particulates exposing on their surfacemolecules of one or several carbohydrates. Each nano-particulate isformed of a core nano-particle closely associated with a sweetenercarbohydrate coating.

Nano-particles that serve in the implementation of this inventionpreferably satisfy a number of conditions, including the following:

-   -   a) said particles are preferably between 3 nm to a 100 nm in        size, most preferably 5 nm to 50 nm, wherein the term “size” as        used herein is understood to denote the maximal distance between        two points on the nano-particle;    -   b) said particles contain as part of their molecular        constitution, oxygen that is exposed on the surface of the        nano-particle;    -   c) said particles are dispersible but not soluble in water;    -   d) said particles are compatible with food.

Illustrative examples of the foregoing are given below. They can serveas an easy to follow guide by any competent chemist or food engineer.

Nano-Silica

Nano-silicas, generally made by precipitation processes in an aqueousphase, may be considered to be condensation products of silicic acidSi(OH)₄. They carry on their surface virtually the bulk of the —OHgroups that did not take part in the condensation that forms the Si—O—Sichains that define the nano-particle. These hydroxyls interact stronglywith water by virtue of hydrogen bonding and other intermolecularforces—an extensively studied fundamental phenomenon. The oxygen ofSi—O—Si chains that is exposed on the surface also interacts with water,though to a lesser extent. These interactions with water are replaced(as explained in detail further below) by interactions withcarbohydrates to form the particulate sweet composites claimed by theinvention. Silica liberated on ingestion of such composites is notabsorbed into the human body and thus is inherently harmless. In fact,as is known, fine silicas serve in industrial food production, forexample as consistency modulators.

Nano-Cellulose

Cellulose (C₆H₁₀O₅)_(n) is a polymer formed in plants by condensation ofglucose. Cellulose is inherently linear. When reduced to nano size rangethe nano-particles have the shape of fibrils that are water insolubleand that expose on their surface hydroxyls attached to the C₆ carbonchain of the constituent glucose units as well as oxygen of the polymerforming C—O—C bonds. Carbohydrates can be made to associate withnano-cellulose to form compositions as described for nano-silica.Cellulose liberated on ingestion is similar to cellulose consumed infruit and vegetables and thus obviously harmless and possiblybeneficial.

A food technologist will consider a large variety of carbohydratepolymers as well as other organic polymers that are accepted foodingredients and that in nano sizes could serve as cores in constructingsweetener compositions. Similarly inorganic nano-particles other thansilica that are innocuous or desired for a special or incidental purposemay be considered e.g. Barium Sulfate.

It was surprisingly found according to the present invention that ifwater is eliminated from an aqueous suspension of strongly hydratednano-particles that contains carbohydrates in solution—provided that theelimination of water is very fast—association of nano-particles andcarbohydrates takes place. The extent of the association varies with theparticular technology adopted and specifics of materials, proportionsetc. It can be assessed by the rate and extent of unassociatedcarbohydrates recovery when the dry raw composition formed indehydration, in fine powder form as a rule, is redispersed in water. Themost relevant assessment with respect to the present application isnaturally the comparative evaluation of sweetness of the selectedsweetener carbohydrate in free unassociated form and when in acomposition. Such comparative evaluation tests are described inconnection with the examples further below.

A speculative explanation of dehydration-mediated association would bethat oxygenated groups on the nano-particles and on the carbohydrates,transiently in a water-deprived state, interact in an energy loweringprocess similar to hydration as if carbohydrate, through its hydroxyls,replaces water. Naturally, some hydroxyls on the nano-core couldinteract with carbohydrate hydroxyls with water elimination. Thishowever is irrelevant as all carbohydrate values are recovered onhydrolysis. The mode of preparation and the measure of sweetness of aspecific composition defines it fully in the terms of the presentinvention.

All modes of very fast drying should be suitable for making compositeswith the proviso that temperatures entailing carbohydrates decompositionneed be avoided. Flash evaporation is an effective mode which may beapplied through several well known technologies. Thus for instance asuspension of nano-cellulose in aqueous sucrose can be effectively driedby spray-drying in nitrogen, or, spread as a thin-layer, dried undervacuum—conditions which prevent oxidation, while preferably controllednot to exceed 150° C. to prevent thermal degradation.

While the invention will now be described in connection with certainpreferred embodiments in the following examples so that aspects thereofmay be more fully understood and appreciated, it is not intended tolimit the invention to these particular embodiments. On the contrary, itis intended to cover all alternatives, modifications and equivalents asmay be included within the scope of the invention as defined by theappended claims. Thus, the following examples which include effectiveembodiments will serve to illustrate the practice of this invention, itbeing understood that the particulars shown are by way of example andfor purposes of instructive discussion of effective embodiments of thepresent invention only and are presented in the cause of providing whatis believed to be the most useful and readily understood description offormulation procedures as well as of the principles and conceptualaspects of the invention.

In the examples below the materials that were used were:

-   -   1) sucrose purchased in a grocery described on the package as        “pure granular sugar”.    -   2) Commercial colloidal silica by DuPont “LudoxSK, Silica (as        SiO₂) 25 wt %; Specific surface area, 230 m²/g”.

EXAMPLE 1

5.75 g of sucrose were dissolved in 10 g LudoxSK (which contained 7.5 gwater and 2.5 g silica) heating gently to about 50° C. to decrease theviscosity and expedite dissolution. About 10 g of the resultant liquidmaterial was spread evenly on a Petri dish of 7 cm diameter and put inan electric oven at 60° C. to dry overnight. The solution prior todrying was marked E1-1 and the crude composition according to thepresent invention which was obtained as dry powder was marked E1-2. Thislast was calculated and analytically confirmed to consist overall of 70%sucrose and 30% silica.

EXAMPLE 2

5.75 g of sucrose were dissolved in 10 g LudoxSK and 1 ml H₂O added todecrease the viscosity. The liquid thus obtained could be dispersed froma nozzle under mechanical pressure as a fine fog. Experiments wereperformed in a bench-top spray drier consisting of a cylindrical vesselfed from the top with liquid by a nozzle accepting the liquid underregulated pressure and by vapor fed through a pipe concentric with thenozzle. Powder collection and vapor exit were provided for byconventional technology. Each experimental run was started by feeding,at atmospheric pressure, 170° C. superheated steam to raise the dryerchamber exit temperature to 110° C. at which point the spraying processwas started and the temperature maintained throughout at 110° C./120° C.by adjusting steam flow. A preliminary test was done in drying a 40%sucrose solution under the conditions described above. The sucrose wasrecovered as a fine powder displaying a very light yellowish tinge butno change in taste compared to the input sugar could be perceived.Several runs of sucrose solution in LudoxSK were subsequently madewhereby the corresponding composition, according to the presentinvention—marked

E2—70% sucrose, 30% silica by calculation as well as by analysis (thusequal in components content to E1-2)—was obtained in consistent tasteproperties.

EXAMPLE 3

The dehydration in this case was effected in the same spray drier as inExample 2 applying a superheated vapor but differed from the former withrespect to two operational parameters:

-   -   a. The superheated vapor consisted of 2-propanol at 160° C.;    -   b. The spray chamber was maintained at 90° C.

In a preliminary run with 40% sucrose solution perfect sucrose recoverywas established. The crude composition (sucrose/silica 70/30) of thisexample was marked E3.

EXAMPLE 4

15.75 grs of LudoxSK/sucrose solution (as in Example 1) were introduceddrop-wise by a pressure dispenser into 200 grs of liquid 2-propanolmaintained at 120° C. in an autoclave. The pressure was then lowered byreleasing vapor (which consisted of IPA and H₂O) whereby atmosphericpressure was established and the temperature came down to 83° C. (whichis close to 82.5° C. the B.p. of 2-Propanol under atmospheric pressure).The contents of the autoclave were gently poured into a separatoryfunnel and the lower liquid slurry phase was separated and dried undervacuum. The nearly colorless powder obtained was marked E4. The upperliquid phase was analyzed and found to contain no H₂O and only traces ofsucrose.

EXAMPLE 5 Comparative Sweetness of Sucrose and Sucrose/Nano-SilicaCompositions

Sweetness evaluations were made by the standard tasting panel procedure.The reference was a 7.5 sucrose solution in 100 water evaluated incomparison with a 10 (presumably derived from 7.5 sucrose) of each crudecomposition in 100 water. All compositions dispersed readily in water toform clear to slightly opalescent liquids. In cases of enhancedsweetness—comparisons were made with solutions with increasedconcentrations (marked C) expressed as sucrose per 100 water. Anenhancement factor was defined by C/7.5. The results are tabulatedbelow. The tasted solutions were re-tasted after 24hrs. No significantchanges in sweetness were observed.

COMPOSITION E1-1 E1-2 E2 E3 E4 Description Mixture prior to 60° C. slowSuperheated Solvent Superheated evaporation drying steam spray vaporspray liquid solvent drying drying dehydration Sucrose 7.5 Possibly15/16 14/18 18/20 equivalent C marginally over 7.5 Enhancement 1 1 2 22.5 factor nil nil twofold twofold 2.5-fold enhancement enhancementsweetness sweetness sweetness Estimated % of unassociated sucrose if atenfold 92% 92% 85% enhancement is assigned to the composition accordingto the present invention Estimated % of unassociated sucrose if afivefold 75% 75% 62% enhancement is assigned to the compositionaccording to the present inventionThe tabulated comparative sweetness values of the sucrose/silicacombination of the four examples make it clear that:

-   -   1. In aqueous solution the sucrose is unaffected by the presence        of nano-silica before or after drying by a slow dehydration        process as in Example 1.    -   2. Sweetness enhancement occurs when the drying is driven by a        fast dehydration process such as vaporizing water under fast        Heat Transfer at a considerable AT (Examples 2&3).    -   3. Sweetness enhancement does also occur through fast        dehydration driven by solvent extraction of water at a        temperature above the B.p. of the solvent as in Example 4.

The foregoing results can be simply explained by assuming crudecompositions consist of sweetener carbohydrate recovered unchanged bydrying and the composition according to the present invention in whichcarbohydrate is associated with a core nano material whereby sweetnessenhancement occurs. Thus enhancement values observed with respect to anycrude composition do not quantify the enhancement ultimately obtainableby a selected pair of a core nano and a carbohydrate sweetener asillustrated by arbitrarily assumed enhancements and the computedunassociated free carbohydrate content in the two bottom rows of theTable.

The practice of this invention advantageously involves only well knowntechnologies and benefits from a very broad options space of materialsand of processes for creating novel, purpose-built sweetenerseconomically. For any pair of nano-core/carbohydrate selected fordevelopment optimization can put into play several adjustableparameters: core/carbohydrate ratios that are fed to dehydration; typesof dehydration; fractionations of crude composition obtained in eachsetting of foregoing options for enhancement levels of sweetness—all ofwhich represent manipulations that will be obvious to a practicingengineer.

A speculative explanation of sweetness enhancement may be constructed ofthree assumptions:

-   -   a. Carbohydrates in a composition according to the present        invention are likely to be perceived by sweet receptors.    -   b. The nano size of the particles of the composition according        to the present invention makes for far lower diffusion rates        that characterize non-associated carbohydrate molecules thereby        prolonging sweetness perception.    -   c. The nano size of the particles of the composition according        to the present invention makes also for its interacting        concurrently with several proximate receptors resulting in the        intensification of sweetness perception.

Assumption (a) is validated by experimental facts presented in thisapplication. Assumptions (b) and (c) could well be elements of a singlemechanism.

It will be evident to those skilled in the art that the invention is notlimited to the details of the foregoing illustrative examples and thatthe present invention may be embodied in other specific forms withoutdeparting from the essential attributes thereof, and it is thereforedesired that the present embodiments and examples be considered in allrespects as illustrative and not restrictive, reference being made tothe appended claims, rather than to the foregoing description, and allchanges which come within the meaning and range of equivalency of theclaims are therefore intended to be embraced therein.

1. A sweetener composition comprising a core, food-compatible,nano-particle in association with a sweetener carbohydrate, wherein saidnano-particle comprises exposed oxygen molecules along the surfacethereof which associate with said sweetener carbohydrate which adheresthereto, and wherein said core nano-particle, with said sweetenercarbohydrate coating exhibits enhanced sweetness compared to acomparable amount of sweetener carbohydrate in free unassociated form.2. A sweetener composition according to claim 1, wherein saidnano-particles are of a size of between about 3 nm and 100 nm.
 3. Asweetener composition according to claim 1, wherein said nano-particlesare of a size of between about 5 nm and 50 nm.
 4. A sweetenercomposition according to claim 1, wherein said nano-particles aredispersible in water.
 5. A sweetener composition according to claim 1,wherein said nano-particles are substantially water-insoluble.
 6. Asweetener composition according to claim 1, wherein said nano-particlecores consist of inorganic nano-particles.
 7. A sweetener compositionaccording to claim 1, wherein said nano-particle cores consist ofnano-silicas.
 8. A sweetener composition according to claim 7, whereinsaid nano-silicas carry on their surface —OH groups and Si—O—Si chains,and the oxygen components thereof are linked to said associatedcarbohydrate groups.
 9. A sweetener composition according to claim 1,wherein said nano-particle cores consist of organic nano-particles ofpoly-carbohydrates and derivatives thereof that are substantiallywater-insoluble below 50° C.
 10. A sweetener composition according toclaim 9 wherein said nano-particle cores consist of low solubilitystarches.
 11. A sweetener composition according to claim 1, wherein saidnano-particle cores consist of nano-cellulose.
 12. A sweetenercomposition according to claim 9, wherein said nano-particle coresconsist of ethoxycellulose.
 13. A sweetener composition according toclaim 9, wherein said nano-particle cores consist of cellulose acetate.14. A sweetener composition according to claim 1, wherein said corenano-particle displays on its surface oxygen molecules contained in itschemical composition that are associated with said coating carbohydrategroups.